CN1139482C - High-performance absorbent structure - Google Patents

Abstract

Disclosed is an absorbent structure having wet integrity higher than about 4.0 kN/gsm, softness higher than 8.0/J, pliability higher than about 70/N, and providing a substantially dry liquid-accepting surface after receiving a quantity of liquid. The structure includes an upper ply having an upper fluid receiving surface and a lower surface and including (i) a top stratum including synthetic matrix fibers bonded with a binder, the matrix fibers having length from about 2 to about 15 mm; (ii) a middle stratum in fluid communication with the top stratum, the middle stratum including natural fibers, superabsorbent particles and a binder; and (iii) a bottom stratum in fluid communication with the middle stratum, the bottom stratum including natural fibers and a binder. The structure also includes a lower ply in fluid communication with the upper ply, the lower ply having an upper surface and a lower surface and including at least one stratum including natural fibers, superabsorbent polymer particles, and a binder, wherein the lower surface of the upper ply has a surface area less than about 80% of the upper surface area of the lower ply.

Description

High-performance absorbent structure

The cross reference of related application

The application has required based on US provisional application serial number No.60/116 according to 35 U.S.C. § 119, the priority of 036 (submission on January 11st, 1999), and its whole disclosures are introduced into for referencial use.

The field of the invention

The present invention relates to be used for comprise the high power capacity of the absorbent products of baby diaper, adult's incontinence articles, sanitary towel etc., the thin and absorbent structure of high comfort.More particularly, the present invention relates to contain the absorbent structure of matrix fiber, binding agent and super absorbent polymer, this structure has x-directivity fluid storage pattern (profile).

Background of the present invention

Absorbent structure is considerable in the many disposable absorbent articles that comprise baby diaper, adult's incontinence articles, sanitary towel etc.

These and other absorbing products is provided with the absorbability core usually to accept and reservation body fluid.This absorbability core is sandwiched between the dough sheet (its function is to allow liquid enter into core) and the impervious tergite of liquid (its effect is to be embedded liquid and to stop flow of liquid to arrive on the clothes of this absorbing products user through absorbing products) of fluid permeable usually.

Diaper and adult's urinary incontinence usually comprise by isolating fiber, cellulosic batts or knitmesh loose, that fiber nappy, hydrophilic, cellulose family constitutes with the absorbability core of bedding and padding.This core also can comprise super absorbent polymer (" SAP ") granule, pellet, fragment or fiber (the general name granule ").

In recent years, the demand for thinner and more comfortable absorbing products increases day by day on the market.This based article can be by reducing the thickness of diaper core, by increasing the particulate amount of SAP and obtaining to reduce thickness and therefore to increase density by rolling or compressing this core.

Yet the high density core can not resemble and absorb liquid apace the less dense cores, because the densification of core causes littler active porosity size.Therefore, in order to keep suitable Liquid Absorption, being necessary to provide than high density absorbability core has the low-density layer of large aperture size more to improve the absorption speed of the liquid that is discharged on the absorbing products.This low-density layer typically is called as securing layer.The design of multi-layer, absorbing core comprises more complicated manufacture process.

For example the storage layers of disposable diaper part generally forms from loose, nappy cellulose in conversion process on the spot.This cellulosic material can't obtain with preformed shape usually, because it demonstrates inadequate net intensity, this lacks fiber combining or entanglement owing to it, and directly unwinding or disentanglement are on the equipment of making the absorbability bedding and padding and handle in this equipment.

Some absorbing products are from convoluted non-braided material manufacturing as ultrathin women use sanitary napkin.The previously prepared absorbability core material of one volume as raw material by direct unwinding in the absorbing products conversion equipment and needn't use for playing wool type product such as a diaper and the normal desired defiber step of urinary incontinence bedding and padding.This nonwoven knitmesh is typically bonded in one way or fixed, and this mode makes it enough intensity be arranged so that handle in conversion process.The absorbent structure that makes from this nonwoven knitmesh also can contain the SAP granule.Yet for requiring to obtain and absorbing a large amount or the situation of the body fluid gushed out, these absorbent structures usually are not enough.In these cases, monolithic shape absorbent material usually is not enough to utilize fully this absorbability core, because this liquid is not to be distributed in this structure on the length direction of absorbability core.As a result, on many zones of absorbability core do not utilize.

The knitmesh consolidation mechanism that uses in the convoluted method of making the preform core provides intensity and dimensional stability as knitmesh.This type of mechanism comprises the latex bonding, and with thermoplastic or bicomponent fibre or thermoplastic powder bonding, water is knitted entanglement, pin perforation, combing etc.Yet this class binding material provides more inflexible core, usually can not adapt to the shape of human body well, especially require to fit well obtain and those situations when containing the body fluid of high volume under.

The pliability of absorbability core and flexibility are to guarantee that the absorbability core can easily allow itself to adapt to the shape of human body or the shape of the assembly (for example another absorbability synusia) of contiguous absorbing products is necessary with it.This stops conversely forming slit and passage between absorbing products and the human body or between the various parts at absorbing products, causes undesirable infiltration in this absorbing products in addition.

The integrity of absorbability core is to guarantee that the absorbability core is indeformable and not demonstrate discontinuity necessary in consumer's use.This type of distortion and discontinuity can cause the decline of overall absorption and capacity and the increase of undesirable seepage.Former absorbent structure lacks pliability, integrity, one or more in pattern absorbability and the capacity.For example, common (short fiber oar) core is owing to its height pliability and flexibility have good adaptability, but meanwhile because its poor integrity and in use cracked easily.As another example, some agglutinating core has good dry integrity as the core from cellulose fluff oar air lay manufacturing, that be densified to 0.35g/cc, but has the adaptability of poor wet integrity and difference.

Absorbent material described here demonstrates the x-directivity and stores pattern, the good combination of adaptability and integrity.This is in conjunction with the comfortableness that provides improved fluid to obtain and be embedded and increase and the potential probability of seepage of minimizing.In addition, the improvement integrity of the absorbent material disclosed herein surface of having reduced absorbent material danger that deforms and the skin of protecting user better prevents to contact with liquid.

General introduction of the present invention

The present invention relates to have the wet integrity that is higher than about 4.0mN/gsm, be higher than the flexibility of 8.0/J, be higher than the pliability of about 70/N and a kind of absorbent structure of exsiccant liquid receiving surface basically is provided after accepting certain amount of fluid.This structure comprises that is gone up a synusia, and this synusia has last fluid receiving surface and lower surface and comprises: go up basic unit, basic unit comprises that this matrix fiber has about 2 to about 15mm length with the agglutinating synthetic substrate fiber of binding agent on this; Realize the middle basic unit that fluid is communicated with last basic unit, this centre basic unit comprises natural fiber, superabsorbent particles and binding agent; With realize the underlayment that fluid is communicated with middle basic unit, this underlayment comprises natural fiber and binding agent.This structure also comprises a following synusia that is communicated with last synusia realization fluid, this time synusia has upper surface and lower surface and comprises at least one basic unit that comprises natural fiber, superabsorbent polymer particles and binding agent, its at the middle and upper levels the surface area that lower surface had of sheet be lower than following synusia upper surface area about 80%.

The summary of accompanying drawing

Fig. 1 a-1d has described to comprise the absorbent structure of the present invention of absorbability synusia and following absorbability synusia.Fig. 2 is the sketch map of the modification anchor clamps that use in the Gurley assay device.Fig. 3 has described to be used to measure the sketch map of the device of flexibility.

Detailed description of the present invention

All lists of references of quoting are in this application all introduced for referencial use. For the inconsistent situation of technical term, be subjected to the constraint of disclosure text.

The present invention includes the absorbent structure of at least two synusia of being made up of agglutinating absorbent material, wherein these synusia realize that mutually fluid is communicated with.With reference to figure 1a, this structure comprises: short synusia 2 and (b) the longer following absorbability synusia 4 gone up that (a) has three basic units 6,8 and 10.Generally speaking, the surface area of the bottom surface of last synusia 2 be lower than the following upper surface of synusia 4 surface area 80%.This arrangement setting and single-layer sheet core material structure advantage Comparatively speaking can make this absorbent material be embedded liquid better during consumer uses this absorbing products and fully obtain utilizing.

With reference to figure 1b, be mainly to occur in the front 16 and 18 zones, center of absorbability core from the human body exhaust fluid by the advantage that provides above-described two-layer chip architecture to obtain.The present invention provides more absorbability capacity in the zone of this core of discharge liquid etch.In addition, the gross density of last synusia 2 is lower than the gross density of synusia 4 down.This difference of density makes has improved liquid acquisition and rewetting function, because because the capillary tension gradient between each synusia, liquid enters into down the synusia from last synusia.

Synusia be should go up and binding agent and SAP granule contained with this time synusia both.Generally speaking, synusia contains the SAP granule of higher concentration on this than following synusia.This time synusia contains and is equivalent to the granule of 30%SAP at least of synusia weight down.The SAP granule of high concentration provides high absorptive capacity and liquid reserve capability in absorbent structure.On the other hand, the low concentration of SAP granule in last synusia is ideal, and (this will stop under the fluid inflow downwards in the synusia) can be avoided because gel blocking-up in this part of absorbent structure.

In the present invention, this SAP granule can be dispersed in the substrate of fiber and binding agent.In addition, this SAP granule can be placed in this structure interior discrete locations or zone.For example, with reference to figure 1c and 1d, this SAP granule can be put into the narrow passage 20 along this absorbability core.The particulate passage of SAP is then by the channel separation with the agglutinating fiber 22 of binding agent.Particulate this discrete layout of SAP makes this granule to be embedded better, promotes liquid flowing on the Z-direction (because having seldom or do not have the existence in the zone of SAP) and makes fluid flow and core soaks suction along the length direction (x-direction) of core is easier.But have seldom or do not have the particulate zone of SAP in addition densification to improve integrity and more to produce higher capillary tension in the fine pore.Preferably, along the length direction densification in addition of absorbent structure.Therefore the pliability of this material is kept, especially on y-direction (crossing this core).

With reference to figure 1a, show the schematic cross sectional view of preferred absorbent structure of the present invention.This absorbent structure comprises synusia 2 and following synusia 4.Last synusia 2 comprises three basic units 6,8 and 10 and preferably manufacture single air-laid structures.Last basic unit 6 is low-density securing layers, and the latter comprises the wettable synthetic fibers of 50-99wt%, the synthetic fibers of preferred 75-90wt%, and the surplus of basic unit is a bonding material.Owing to compared than low-density with each following layer, more large aperture size and lower wettability, last basic unit 6 does not have liquid, aqueous core to soak energy-absorbing power in essence.Fluid easily from it soak downwards below being drawn onto easier moistening and more fine pore, the more highdensity basic unit.Last basic unit 6 comprises that thickness is the 2-30 danier, the synthetic fibers of preferred 6-15 danier.These synthetic fibers have 2-15mm, the length of preferred 4-12mm.Randomly, but this fiber shrinkage and have various shape of cross sections.The last basic unit 8 of last synusia 2 has 20-120gsm (g/m ²), the Unit Weight of preferred 30-60gsm.

The middle basic unit 8 of last synusia 2 mainly is made of and also contains the SAP granule natural fiber.In this basic unit the particulate content of SAP be on the 5-60% of synusia 2 weight, preferably go up the 20-40% of synusia weight.The Unit Weight of the middle basic unit of last synusia is 50-1000gsm (g/m ²), preferred 80-300gsm.The middle basic unit of last synusia can bond with the binding agent of any adequate types.Preferably, this binding agent is the bi-component thermoplastic fibre, in the middle of being present in the amount of the 1-15% of the Unit Weight of basic unit in the middle of being equivalent to and preferred 5-10% in the basic unit 8.

The underlayment 10 of last synusia 2 comprises agglutinating natural fiber.This one deck for example can be with the agglutinating wet-laying cellulose of binding agent (typical case is used for paper technology) tissue.Randomly, this organizes also available for example one or more heat-activation binding agent (as bicomponent binder fibers) dipping, this binding agent can in the net solidification process, be activated and then will this tissue and the basic unit above it bond together.The underlayment of last synusia also can form in the forming process of last synusia, for example as agglutinating air lay shop coating.Any suitable binding agent basic unit 10 that can be used to bond.If for example, binder fibre is used for this purpose, it exists with the 3-15% of the Unit Weight of underlayment 10 and the amount of preferred 5-10%.Other binding agent also is suitable as latex type binding agent or the dispersible binding agent of water that uses in wet papermaking process usually.Basic unit 10 has 10-200gsm, the Unit Weight of preferred 15-90gsm.

Following absorbability synusia 4 is the particulate adhesive structures of natural fiber and SAP.Generally speaking, the amount (wt%) in the SAP granule infra synusia 4 is higher than the amount of SAP granule in last synusia 2.This time synusia contains SAP granule and the preferred 40-60wt% of 30-80wt%.

Randomly, following synusia 4 can contain basic unit 12, and the latter comprises that agglutinating natural fiber is used for being embedded the SAP granule in basic unit 13 or the basic unit below it better.Any suitable binding agent can be used for boning structure of this time synusia.If, for example, use binder fibre, it exists with the 1-8% of synusia weight under being equivalent to, the amount of preferred 2-5%.

Generally speaking, the gross density that has of following synusia 4 is higher than the gross density of synusia 2.The density of following synusia can be 0.1-0.35g/cc (gram/every cubic centimetre), preferred 0.15-0.25g/cc.The density that is higher than 0.35g/cc is undesirable, because find the shape adaptability of reduction for this compact texture.The Unit Weight of following synusia can be 100-1000gsm, preferred 150-400gsm.

Absorbent structure of the present invention can and use various raw materials such as natural and synthetic fibers by various forming methods, and various types of SAP granules and dissimilar binding agents (comprising fiber, powder or liquid) are made.

The example that can be used to the type of the natural fiber among the present invention comprises: from Cotton Gossypii, softwood pulp and/or bardwood pulp, the nappy cellulose fibre of Caulis et Folium Oryzae preparation, Ke Fu (keaf) fiber is by the cellulose fibre of chemistry, machinery and/or heat treatment modification, the fiber of keratin fiber as obtaining from feather, and with the artificial chopped strand of natural polymer such as cellulose, chitin and keratin manufacturing.The example of suitable synthetic substrate fiber comprises polyethylene, polypropylene, polyester (comprising poly terephthalic acid diol ester (PET)), polyamide, cellulose acetate and rayon fiber.The synthetic fibers that some is hydrophobic as TPO, should carry out surface treatment to improve wettability with surfactant.

US patent No.5,147,343; 5,378,528; 5,795,439; 5,807,916; With 5,849,211, various super absorbent polymers and manufacture method have been described, therefore introduce for referencial use here.The example that can be used for the particulate type of SAP among the present invention comprises the super absorbent polymer of granular form, as irregular pellet, and spherical particle, chopped strand and other elongated piece.Term " super absorbent polymer " or " SAP " normally refer to crosslinked water-soluble polymer.Existing known water-soluble polymer such as the carboxyl group polyelectrolyte of making produces the method for hydrogel formation with material, is commonly referred to as super-absorbert material or SAP now, and all knows the absorbability of using this type of material to strengthen disposable absorbent article.Also have known that carboxylated polyelectrolyte is in addition crosslinked to obtain the method for super absorbent polymer.Being used to implement SAP granule of the present invention can buy from a plurality of manufacturers, comprising Dow Chemical (Midland, Michigan State), Stockhausen (Greensboro, and Chemdal (ArlingtonHeights, Illinois) North Carolina state).A kind of common granular super absorbent polymer is based on poly-(acrylic acid), and it has carried out crosslinked in polymerization process with any in the polyfunctional group comonomer cross-linking agent known in the many kinds of prior aries.The example of multifunctional cross-linking agent sees US patent No.2,929,154; 3,224,986; 3,332,909; With 4,076,673.Other water miscible polyelectrolyte polymers is known to be can be used for by crosslinked preparation super-absorbent material, and these polymer comprise carboxymethyl starch, carboxymethyl cellulose, and chitosan salts, gelatin salt, or the like.Yet they generally are not used for strengthening the absorbability of disposable absorbent article on commercial scale, mainly due to low absorption efficiency or expensive.

The example that can be used for the binding agent in the absorbent structure of the present invention comprises the polymeric binder of solid or liquid form.The term " polymer " binding agent " be meant and can producing any chemical compound of cementation between fiber between the matrix fiber with the integrity that strengthens synusia.Simultaneously, binding agent can be chosen wantonly binder fibre and SAP particle bond are in the same place.For example, the dispersion of natural or synthetic elasticity latex can be used as binding agent.The example of suitable latex adhesive is an acrylate, the polymer of vinyl acetate and styrene-butadiene and copolymer.Known thermoplastic fibre or powder provide cementation after also being used in absorbent structure being heated to the fusing point of thermoplastic fibre or powder in the prior art.Can be used in other binding agent of stablizing absorbent structure of the present invention and comprise the binding agent that is used for the viscose fibre cellulose fiber.These reagent comprise the polymer that is dispersed in the water, and it is being applied over that cellulosic solidifies after online and is boning producing between the fiber or between fiber and SAP granule.The example of this class reagent comprises various cationic starch derivatives and the synthetic cationic polymer that contains crosslinkable functional group, as polyamide-polyamine epichlorohydrin adducts, cationic starch, dialdehyde starch etc.Any conjugate of above-described polymeric binder can be used for stablizing structure of the present invention.In one embodiment, the binding agent among the present invention is a binder fibre, and it comprises the SAP granule that is lower than about 10wt%.In another example of the present invention, binder fibre accounts for below about 7wt% of absorbent structure.

The hot strength that " integrity " used herein is the cellulosic sheet material measuring after with respect to unit Unit Weight nominalization, and serve as to destroy unit of force (milli newton, mN) expression on the needed x-direction of 1 inch wide sample of sheet material with nominal Unit Weight for every 1gsm.In order to measure the absorbability core or to be purchased the wet integrity (wet tensile strength) of absorbent products, use following procedure:

1. prepare 1 inch * 4 inches samples.For sample, cut 4-inch size in the vertical with obvious vertical and horizontal.

2. remove any removable plastics tergite, mulch or the synthetic material that obtains only stay core.

3. weighing sample.Use pipet or spray bottle 0.9% saline solution (with the amount of the twice that equals example weight) to be applied to the center (example: sample weighing 1.00g of sample.Apply the 2.00g saline solution, amount to 3.00g together).

4. sample inserted tensile testing machine (for example Thwing-Albert LT-150 versatile material testing machine, default software set value is used for test) by being placed in the press fixture.

5. begin test.

6. when test is finished, write down shown result.These results comprise peak action power, peak value percentage elongation, elongation at break, peak energy, and ceiling capacity.

Here employed wet integrity is defined as the peak action power by using above program to measure.The wet integrity of absorbent structure of the present invention is higher than 4.0mN/gsm and preferably is higher than 6.0mN/gsm.

The flexibility of absorbent structure is a key factor of the overall adaptive of this structure.Here employed " flexibility " is the inverse of this sheet material energy needed value of compression, and this sheet material is an absorbent structure in this case.For compression sheet material energy needed value is big more, flexibility is low more.

In order to measure the flexibility of core, program (improved compression test) below using:

1. prepare sample and (, downcut than thickness portion (if in uneven thickness) by cutting 4 inches * 8 inches sheets from diaper if sample is a diaper.For the sample that obvious vertical and horizontal are arranged, cut 8-inch size in the vertical).

2. allowing plastics tergite and cladding material be retained on the sample (is fitted in and is purchased on the diaper sample).If test prototype core product, plastics tergite (Exxon EMB-685 polyethylene film) is fitted to the bottom of sample and the surface that mulch (the spunbond polypropylene of 15gsm Avgol) fits to sample (with sample same size is arranged, the spraying a little binder adheres to).

3. the improved compression test of program (for example, Thwing-Albert LT-150 versatile material testing machine): the compression test of using following non-damaged setting value: destroy detection method=% and fall down/displacement, destruction value=% falls down=and 50, distance shelves (distance traps)=0.3in./0.5in./0.7in., unit: distance/displacement=inch; Power=g, test speed=1in./min.All other setting values are retained in damaged value.

4. use and customize anchor clamps depicted in figure 3 sample is inserted in the tensile testing machine.Sample inserts with its edge, makes it be compressed on y-direction (4-inch direction), and two edges have 1 inch in the customization anchor clamps, therefore stays 2-inch slit.

5. begin test.

6. when deflection surpasses 0.7 inch, push press fixture from the teeth outwards and come analog sample to break down and stop test (not influencing result of the test) then.Write down shown result.These results comprise peak action power, peak value deflection, maximum deflection, peak energy and the energy under maximum deflection and the active force under the distance shelves.

The value that is used to calculate flexibility is the energy under maximum deflection, represents with joule.Energy under the maximum deflection, E _{D max}, be to calculate according to following formula: $E_{d\max }=\underset{d\min }{\overset{d\max }{\∫}}F{d}_d$

Work as E _DmaxWhen being the energy under maximum deflection, F is the power under given deflection d, and dmin and dmax are respectively the deflections during in on-test with in off-test.

Flexibility, S here is to define according to following formula:

S=1/ (energy under the maximum deflection).

This result, S here is to represent with 1/ joule (1/J).

Generally speaking, the flexibility of overall absorption structure of the present invention should be higher than 8.0/J, preferably is higher than 15/J.

The pliability of absorbent structure also is a key factor of the overall adaptive of sheet material.Here employed " pliability " is the inverse of the value of the needed power of crooked this sheet material, and this sheet material is an absorbent structure of the present invention in this case.For the needed power of crooked this sheet material is big more, the pliability of sheet material is low more.

Pliability can use the Gurley assay device (Model 4171, Gurley PrecisionInstruments, Trey NY) measures by following procedure.

1. as far as possible accurately cut sample and become 1 inch * 3.25 inches.If definite vertical and horizontal are arranged, on all directions and in each test, cut a sample.

2. on the former anchor clamps that are equipped with on the Gurley assay device, assemble the anchor clamps that oneself customize as shown in Figure 3, and tighten the small upper thumb screw and fixed (, having illustrated to be the used customization anchor clamps of sheet material higher Unit Weight, senior (lofty)) referring to Fig. 2.These customization anchor clamps design in such a way, make not change by the thickness of test material when material inserts in the anchor clamps.If owing to the cause of clamp changes thickness, then the character of structure changes and the result that uses the Gurley assay device to be obtained can be affected.In the method, use the anchor clamps of Fig. 3 to eliminate this undesirable influence.

3., bottom thumb screw long by unscrewing opened the adjustable plate of these customization anchor clamps.By allowing the sample slip just contact former anchor clamps sample is put into anchor clamps until it.2.0 inches of sample should be embedded in the anchor clamps in customization.

4. adjust the height that customizes anchor clamps by the altitude mixture control screw of unscrewing on the former anchor clamps.Adjusting highly makes to be left the point of customization anchor clamps and have 1.0 inches slit between the point of sample engagement lever arm at sample.

5. guarantee 0.25 inch below that extends to the top of lever arm of residue of sample.Guarantee that lever arm can not move.Pressing the motor button makes sample move to lever arm.Continue to pin the motor button up to sample touching (clears) lever arm.When carrying out this operation, the highest numerical value of observing and being recorded on the graduated scale to be reached.Repeat this program in the opposite direction.

6. obtain average two values.In the conversion chart on this device, the distance at center finds coefficient for 1 inch wide * 1.5 inch long sample on position that the employed weight of foundation and this weight are placed and the lever arm.1.0 inches * 3.25 inches samples that use the test of customization anchor clamps are corresponding to 1.0 inches * 1.5 inches samples that do not use the test of customization anchor clamps.Do not customize anchor clamps, 0.25 inch of sample is in former anchor clamps, 0.25 inch below that extends to the top of lever arm, and 1 inch is between the slit.Use the customization anchor clamps, use same 0.25-inch value in the customization anchor clamps; The 1.75-inch fixes thicker sample in addition in the customization anchor clamps.Same 0.25-inch extend to lever arm the top the below and between 1-inch slit is arranged equally.

7. the average reading on the graduated scale be multiply by the suitable conversion coefficient that on conversion chart, finds.

This result is a stiffness, and it is represented with milligram power (mg).Pliability, P is to define according to following formula:

P=10 ⁶/ 9.81* stiffness.

This result, P here is to represent with 1/ newton (1/N).Generally speaking, the pliability of overall absorption structure of the present invention should be higher than 60/N, preferably is higher than 80/N.

In the present invention, by in the preparation of absorbent structure, adopting the one or more combinations in following all the feature to realize high-caliber flexibility, pliability and wet integrity: by the use soft fibre, curl or the shrinkage fiber, by applying soft binder system for example fine or shrinkage binder fibre, elasticity latex binder or water miscible binding agent, by at utmost reducing the amount of binding agent, adopt in the compacting process before curing in the calender line of lower pressure and the sheet material after curing and use lower pressure.Generally speaking, in absorbent structure of the present invention after compacting and/or the calendering density of sheet material should be lower than 0.35g/cc and preferably be lower than 0.3g/cc.

In one embodiment of the invention, in net process, do not use the carrier tissue sheet material.Common use examples of such carriers is organized sheet material and is become the integral part of this structure.Their increase the intensity of knitmesh but also increase its stiffness.

In another embodiment of the present invention, the amount of binder fibre in this structure is less than 10% of this construction weight.In another embodiment, the amount of binder fibre is lower than 7% of this construction weight.Typically, use the binding agent of a large amount, it causes obtaining than high integrality but low flexual absorbent structure is arranged.

In another embodiment of the present invention, the flexibility of this structure and pliability are to realize by the mechanical treatment of total or its component absorbability synusia after the formation of absorbability synusia.This type of mechanical treatment comprises little wrinkleization, allows knitmesh by the roll gap between grooved roller etc.Generally speaking, in these programs, some bonding points in the structure are destroyed, and result, structure become, and more the subsides clothes are comfortable.

The integrity of absorbent structure of the present invention is higher than the integrity of the common core of only using fluffing processing and the manufacturing of SAP powder, and enough height make a slice core can be used in the conversion.Especially, the wet integrity of absorbent structure of the present invention is higher than the wet integrity without the gentle stream of the common core core into the net of binding agent manufacturing.In one embodiment, this absorbability core has the wet integrity greater than 4.0mN/gsm.In another embodiment, this absorbability core has the wet integrity greater than 6.0mN/gsm.In an embodiment again, this absorbability core has the wet integrity greater than 8.0mN/gsm.The wet integrity of the gentle stream of common core core into the net that need not any binding agent is lower and generally is lower than 4.0mN/gsm (seeing Table 1).For common core (in-place molding), integrity has depended primarily on the mechanical interlocking of wool fibre.Because this mechanical interlocking is that partly this is crimped onto disappearance at least to a certain extent owing to a certain amount of curling of fiber with when this material is wetted.The integrity of common core also significantly reduces under wetting state.For need not be any binding agent make but the material of the air lay of high compactionization (as be described in US patent 5,866,242 or 5,916,670 in), fine and close structure mainly keeps together by means of hydrogen bond.Yet hydrogen bond destroys fully when this material is wetted, then this absorbability core become be highly brittle a little less than.

The flexibility of absorbent structure of the present invention and pliability are sufficiently high, and this material easily adapts to the shape of human body or adapts to shape absorbing products and assembly (for example another absorbed layer) its vicinity like this.In one embodiment, the flexibility of the absorbent structure pliability that is higher than 8.0/J and absorbent structure is higher than 60/N.

In order further to improve the level of flexibility, pliability and the wet integrity of absorbent structure, this structure can use various chemistry and/or mechanical means to handle.Do not want to be subjected to the restriction of any theory, can believe,, can obtain flexibility, pliability and the wet integrity of desired level with agglutinating and the proper ratio of agglutinating structural detail not for the given composition of absorbent structure.If between the fiber or the number of the bonding point between this fiber and SAP granule too little, then the wet integrity of this structure is too low so that can't realize this absorbent structure improvement performance during use.When user moves, the structure of this low integrity possibly can't bear mechanical stress and may produce crack and other discontinuity the time, cause the liquid of difference to be embedded and seepage subsequently.On the other hand, if the number of bonding point is too high in absorbent structure, then the low too and structure of pliability and flexibility becomes not too comfortable, has reduced serviceability owing to formed undesirable passage and slit (liquid is by their free-flow and leak out) from absorbing products.

Exemplify can combine with carrier such as cellulose tissue or the synthesis of non-woven fabric use of this absorbent structure as following.This absorbent structure also can combine to use and form absorbent structure with other layer or structure.

In another preferred embodiment, the last synusia of structure is used alone as absorbent structure.The structure of single-layer sheet demonstrates high wet integrity, high flexibility and high pliability, and needing in many application of this attribute can be used for.This type of examples of applications comprises disposable absorbent article such as diaper, health bedding and padding, adult's incontinence articles and gym shorts.

The absorbent structure of single-layer sheet can be according to same quadrat method preparation given among the embodiment relevant with two-layer chip architecture.In addition, the structure of single-layer sheet can be used and adopt the random web-laying equipment of three forming heads to make.Use the example of such machine to list below as embodiment 8-11.

The present invention further illustrates in below the non-restrictive example.

In the following embodiments, Unit Weight (gsm) is listed as desired value.The effective unit weight that is obtained can change in 10% the scope at the most in fluctuation.

Embodiment 1

Absorbent structure combines and assembles by last synusia (assembly A1) and the following synusia (assembly B1) with the following stated.Two absorbability assemblies are by at M ﹠amp; Dry-press process method among the J on the try engine (or air lay method) is made.The mechanical performance and the absorbent properties of this structure are described in table 1, in 3 and 4.Compare with the viewed performance of structure that is purchased described here, this structure shows improved performance, and this is owing to the adaptability of pattern absorbability and optimal level and having both of integrity.

Assembly A1.Use two forming heads, they are added into the raw material of same composition and same amount.This product is applied on carrier upper berth at 40gsm Brand 6810 polyester (polyethylene terephthalate) adhesive-bonded fabrics (PGI).This material has constituted the last basic unit of last synusia.The Unit Weight of middle basic unit and underlayment is identical with forming, this Unit Weight is that 160gsm and composition are 56.3%HPF fine hair (Buckeye Technologies Inc., Memphis, TN), 37.5%Z1049 SAP (Stockhausen, Greensboro, NC) and 6.2%T-255, (2.8dpf danier number/every fiber) thermoplasticity, bicomponent binder fibers (Kosa, Salisbury, NC).Solidifying the thickness that (160 ℃, 1 minute time of staying) are calendered to sheet material with minimum pressure 3mm afterwards.

Assembly B1.The T-255 binder fibre of the Foley Fluff (BuckeyeTechnologies) of adding 75gsm and 3gsm in first forming head (Kosa, Salisbury, NC).Formed layer is the middle basic unit of this time synusia.The last basic unit of following synusia is formed by second forming head, adds the Foley Fluff (Buckeye Technologies) of 55gsm therein, the T-255 binder fibre (Kosa of 12gsm, Salisbury, NC) and the SXM4750SAP of 215gsm (Stocknausen, Greensboro, NC).This product is spread to be applied on carrier, and the latter is a Duni Finner K1801 cellulose tissue (Duni, Kisa, Sweden).This carrier has constituted the underlayment of time synusia.After curing, sheet material is calendered to the thickness of 2mm.

Each assembly can overlay by the 10 * 20cm A1 sheet material with this material on the end of 10 * 40cm B1 sheet material of this material and assemble.Measure at A1 and the eclipsed end of B1 section.

Embodiment 2

By being combined, assembly A2 as described below and assembly B2 assemble a kind of absorbent structure.Two absorbability assemblies are by at M ﹠amp; Dry-press process manufactured among the J on the try engine.In the structure of manufacturing, assembly A2 is synusia under last synusia and assembly B2 are.The mechanical performance and the absorbent properties of this structure are described in table 1, in 3 and 4.This structure shows improved performance, and this is owing to the adaptability of pattern absorbability and optimal level and having both of integrity.

Assembly A2.The middle basic unit of last synusia be by the HPF fine hair that in first forming head, adds 40gsm (Buckeye Technologies, Memphis, TN) and the 2.8dpfT-255 binder fibre of 2.5gsm (Kosa, Salisbury NC) make.Second forming head is used to form the last basic unit of synusia.The HPF fine hair of adding 100gsm in second forming head (BuckeyeTechnologies, Memphis, TN), the Z1049 SAP of 94gsm (Stockhausen, Greensboro, NC) and the 2.8dpf T-255 binder fibre (Kosa of 13gsm, Salisbury, NC).This product is spread to be applied on carrier, and the latter is 48gsm LicontrolTM 381002 (polypropylene) adhesive-bonded fabric (Jacob-Holm Industries, Soultz, France).This carrier has constituted the last basic unit of last synusia.This product is calendered to the thickness of 3.0mm with minimum pressure after solidifying.

Assembly B2.Use two forming heads, they are added into the raw material of same composition and same amount.This product is spread to be applied on carrier, and the latter is a Duni Finner K1801 cellulose tissue.The composition of overall component B2 with Unit Weight of 378gsm is 34.1%FoleyFluff (Buckeye Technologies), 57.1%SXM3950 SAP (Stockhausen, Greensboro, NC), and 4%T-255,2.8dpf binder fibre (Kosa, Salisbury, NC); The surplus of this structure is the carrier tissue of 18gsm.After curing, sheet material is calendered to the thickness of 2mm.

Embodiment 3

By being combined, assembly A3 as described below and assembly B3 assemble a kind of absorbent structure.Two absorbability assemblies are by the dry formed manufactured on the try engine in DanWeb.In the structure of manufacturing, assembly A3 is synusia under last synusia and assembly B3 are.The mechanical performance and the absorbent properties of this structure are described in table 1, in 3 and 4.This structure shows improved performance, and this is owing to the adaptability of pattern absorbability and optimal level and having both of integrity.

Assembly A3. in first forming head, add 60gsm Foley Fluff (BuckeyeTechhologies, Memphis, TN) and the 2.8dpf T-255 binder fibre of 10gsm (Kosa, Salisbury NC), have formed the underlayment of last synusia.Second forming head is used to form the middle basic unit of synusia.The Foley Fluff that in second forming head, adds 98gsm, the SXM70 SAP of 62.5gsm (Stockhausen, Greensboro, NC) and the 2.8dpfT-255 binder fibre of 19.5gsm (Kosa, Salisbury, NC).Wellman 376 * 2 polyester fibers of the length of the thickness of adding 35gsm and 6mm in the 3rd forming head with 15dpf.(AirProducts, Allentown PA) spray with 5gsm with the A-181 latex that is diluted to 10% solids content in the last basic unit of the last synusia that forms like this.This sheet material is calendered to the thickness of 4.1mm with minimum pressure after solidifying.

Assembly B3. use a forming head and add therein 128gsm ND416 fine hair (Weyerhaeuser, Tacoma, WA), the SXM70 SAP of 225gsm (Stockhausen, Greensboro, NC) and the 2.8dpf T-255 binder fibre (Kosa of 22gsm, Salisbury, NC).Apply into this product on Cellutissue 3024 cellulose tissue carrier upper berths.After curing, sheet material is calendered to 1.9 thickness.

Embodiment 4

By being combined, assembly A4 as described below and assembly B4 assemble a kind of absorbent structure.Two absorbability assemblies are by the dry formed manufactured on the try engine in DanWeb.In the structure of manufacturing, assembly A4 is synusia under last synusia and assembly B4 are.The mechanical performance and the absorbent properties of this structure are described in table 1, in 3 and 4.This structure shows improved performance, and this is owing to the adaptability of pattern absorbability and optimal level and having both of integrity.

Assembly A4. in first forming head, add 77.6gsm Foley Fluff (BuckeyeTechnologies, Memphis, TN) and the 2.8dpf T-255 binder fibre of 12.4gsm (Kosa, Salisbury NC), have formed the underlayment of last synusia.Second forming head is used to form the middle basic unit of synusia.The Foley Fluff that in second forming head, adds 102gsm, SP 1186 SAP of 130gsm (Stockhausen, Greensboro, NC) and the 2.8dpf T-255 binder fibre of 28gsm (Kosa, Salisbury, NC).Wellman 376 * 2 polyester fibers of the length of the thickness of adding 42gsm and 6mm in the 3rd forming head with 15dpf.(Air Products, Allentown PA) sprays with 8gsm with the A-124 latex that is diluted to 10% solids content in the last basic unit of the last synusia that forms like this.This sheet material is calendered to the thickness of 5.7mm with minimum pressure after solidifying.

Assembly B4. in first and second forming heads, add all components of equivalent, ND416 fine hair (the Weyerhaeuser that promptly adds 37gsm, Tacoma, WA), 92.3gsm SXM3950SAP (Stockhausen, Greensboro, NC) and the 2.8dpf T-255 binder fibre (Kosa of 5gsm, Salisbury, NC).So the net that forms becomes the underlayment of synusia down.Apply into this basic unit on Cellutissue 3024 cellulose tissue carrier upper berths.In the 3rd forming head, add the ND416 fine hair of 38.5gsm and the 2.8dpf T-255 binder fibre of 8.9gsm, form the last basic unit of synusia down.After curing, final sheet material is calendered to the thickness of 1.45mm.

Embodiment 5

Embodiment 1,2, and 3 and 4 structure is used to analyze wet integrity, flexibility and pliability.The result who is obtained is summarised in the table 1.Several absorbability cores that are purchased disposable infant diaper (sample A, B and C) in table 1, have also been listed and with fine hair and SAP but without any the analysis result of the sample (sample D) of the prepared high density airlaid material of binding agent.The measured value of the elementary structure parameter of test core is shown in Table 2.Other tested core that is purchased has much higher wet integrity and than the core of sample D much higher flexibility and pliability is arranged than all for digital proof in table 1, embodiment 1,2,3 and 4 absorbent structure.

Table 1

Absorbent structure	Wet integrity, mN/gsm	Flexibility, 1/J	Pliability, 1/N
				Embodiment 1	5.2	8.9	72.9
Embodiment 2	7.2	10.2	112.0
				Embodiment 3	8.7	17.8	104.0
Embodiment 4	7.0	10.6	105.2
				Embodiment A	0.8	10.1	175.5
Embodiment B	2.6	12.9	137.8
				Embodiment C	1.5	7.4	117.7
Embodiment D	1.3	5.6	40.2

Table 2

Embodiment	Last core width * length (cm * cm)	Following core width * length (cm * cm)	Surface area (the cm of combination 2)	Last core Unit Weight (gsm)	Following core Unit Weight (gsm)	Grand mean Unit Weight (gsm)	Last core density (g/cc)	Following core density (g/cc)	Grand mean core density (g/cc)	Last core % SAP	Following core % SAP	Grand mean core % SAP
													Embodiment D
	8×20	11×36	396	400	310	472	0.27	0.36	0.31	37.0	51.0	43.0
													Embodiment C			385			759			0.14			26.7
Embodiment B			468			617			0.25			53.5
													Embodiment A			360			649			0.26			43.4
Embodiment 1	10×20	10×40	400	360	375	555	0.12	0.19	0.16	37.5	57.3	47.6
													Embodiment 2	10×20	10×40	400	297.5	360	509	0.10	0.18	0.14	26.1	60.0	44.7
Embodiment 3	9×20	10×40	400	290	390	521	0.07	0.21	0.15	21.6	57.7	42.3
													Embodiment 4	10×20	10×40	400	400	331	531	0.07	0.23	0.14	32.5	55.8	43.1

Embodiment 6

According to the prepared tested liquid acquisition performance of in embodiment 1,2,3 and 4, describing of structure of program.To obtain performance in order estimating, to measure acquisition time, promptly the saline solution absorbability structure for given volume absorbs the time of (till any free fluid disappears from the surface of absorbing material).

Following method is used to measure this acquisition time:

1. before test, sample was nursed one's health 2 hours under 70 and 50% relative humidity in laboratory.

2. preparation standard saline solution (0.9wt%NaCl/DI H2O).If necessary, add dyestuff.

3. measure etch volume and employed load.Intermediate size sample (most diaper of medium size (size #3)) uses the load of 3 * 75ml etch zone and 0.4-psi.The absorbent structure of describing in embodiment 1-4 belongs to this classification.

4. if in laboratory or at assay device (random web-laying equipment), go up and form sample, then be cut into required size.Should be 4 inches * 14 inches and should be 4 inches * 16 inches for the sample that on laboratory bedding and padding make-up machine, makes for the sample that on assay device, makes.If sample is the commodity diapers, cut elastic leg cuff simply, so that the diaper tiling forms.Get the weight/thickness measured value for each sample.

5. by placing Exxon EMB-685 polyethylene film and add cladding material on the plastics tergite, the spunbond polypropylene of 15gsm Avgol prepares the sample of air lay.Guarantee the back plastic sheet material upwards towards the top flap of sample to prevent to take place at the trial seepage.

6. by on base plate, placing sample, foam piece is fixed on the sample top, the etch ring is put into the hole of foams and then the top board of weighing is fixed on the top of foam piece, sample is arranged in the deriving means.

7. set timer and be 20 minutes and be placed on the next door of assay device.

8. hold stopwatch in hands and the another hands is held the graduated cylinder that contains the etch volume, with the preparation etched samples.Fluid is poured in the etch ring.The stopwatch of starting in a flash at fluid touching sample.As far as possible apace from graduated cylinder emptying fluid.When fluid stops stopwatch during by absorption of sample.

9. write down the time that the absorption of sample fluid is spent.In case fluid by absorption of sample, starts 20 minutes timers.

10. after 20 minutes, repeating step 7-9.

11. after another 20 minutes, repeating step 7-9.Annotate: if do not carry out other test after obtaining test, then minute interval of the 20-after etch for the third time can omit.Yet,, must use this 20-minute interval and start other test then if after obtaining test, need to carry out another test (rewetting and maintenance or distribution).

Following formula is used to calculate this and obtains speed:

The result that structure obtained by test implementation example 1,2,3 and 4 is summarised in the table 3.In table 3, also list some absorbability cores that are purchased diaper product sample A, B and C and another is purchased the analysis result of diaper core (sample D), had a basic physical property described in the table 2.Data in the table 3 comprise the result that structure obtained by test implementation example 1,2,3 and 4.The structure of these embodiment is to assemble according to the explanation among Fig. 1.In each case these structures at the middle and upper levels the length of sheet be 20 centimetres.Result in the table 3 proves that the absorbent structure of embodiment 1,2,3 and 4 has the acquisition time than sample D much shorter.It can also be seen that embodiment 3 and 4 absorbent structure have than all tested shorter acquisition times of the core that is purchased diaper.

Table 3:

Absorbent structure	Obtain for the first time speed, ml/s	Obtain for the second time speed, ml/s	Obtain speed for the third time, ml/s
				Embodiment 1	1.16	0.56	0.36
Embodiment 2	1.35	0.86	0.63
				Embodiment 3	2.85	1.29	0.93
Embodiment 4	5.56	2.71	1.83
				Embodiment A	2.01	1.19	0.83
Embodiment E	2.25	1.70	1.24
				Embodiment B	1.90	0.75	0.55
Embodiment C	1.32	0.46	0.33
				Embodiment D	0.91	0.49	0.30

Embodiment 7

According to the prepared tested rewetting performance of in embodiment 1,2,3 and 4, describing of structure of program.In order to estimate the rewetting performance, measure the rewetting amount, i.e. amount that can detected liquid on the surface at absorbent structure after in addition saturated with the saline of specified rate.

Following method is used to measure the rewetting amount:

Design is carried out rewetting immediately and is kept test after obtaining test.This obtains test procedure and must start before this test of starting.If do not need to obtain information, needn't write down acquisition time, yet the pattern of 3 etches of being separated by 20-minute interval must be carried out.It is essential, before starting this test, experienced 20 minutes interval.Sample/formulations prepared from solutions with obtain test (referring to obtaining test documentation) in identical.

1. sample is assumed to be now and obtains test and interference-free for maintenance in the last 20-minute interval by this.Set timer and be 5 minutes and be placed on the next door of assay device.

2. the 10 Buckeye S-22 Blotterpapers (blotting paper) that are cut into the same size of sample are folded in weighing one.

3. remove at sample the weight on foam piece and the etch ring.

4. on sample, place a stacker.

5. on sample, reappose foam piece and weight.Start 5-minute timer.

6. 5 minutes ending, remove weight and weighing one stacker.

Write down the poor of weight between wet and dried paper.Calculate the rewetting amount according to following formula:

The weight (g) of weight (the g)-dried paper of rewetting amount (g)=l Water Paper

Following formula is used to calculate the rewetting reservation amount after etch for the third time:

Embodiment 1,2, tested rewetting amount of 3 and 4 structure and the results are shown in the table 4 of being obtained.Data in the table 3 comprise the result that structure obtained by test implementation example 1,2,3 and 4.The structure of these embodiment is to assemble according to the explanation among Fig. 4.In each case these structures at the middle and upper levels the length of sheet be 20 centimetres.In table 4, also list some analysis results that are purchased the absorbability core (sample A, B and C) of diaper goods and are purchased diaper core (sample D), had the basic physical property described in the table 2.Data in the table 4 show, except the sample of embodiment E has the minimum rewetting retention, all other tested cores have at least 97% rewetting retention.

Table 4

Absorbent structure	The rewetting retention rate, %
		Embodiment 1	97.0
Embodiment 2	98.4
		Embodiment 3	99.4
Embodiment 4	97.2
		Embodiment A	98.5
Embodiment E	92.8
		Embodiment B	99.8
Embodiment C	99.0
		Embodiment D	97.1

Embodiment 8

Make absorbent structure by dry-press process on the DanWeb assay device.The mechanical performance of this structure and absorbent properties are described in table 5 and 6.This structure shows improved performance, and this is owing to the flexibility of optimal level, the combination of pliability and wet integrity.Three forming heads are used to make this absorbent structure.This product is applied on carrier upper berth at the Cellutissue 3024 of the Unit Weight with 18gsm.Before using, this tissue 4gsm bicomponent binder fibers, T-255 (Kosa, Salisbury, NC) dipping, this fiber has the thickness of 2.8 daniers/every fiber.This fiber is deposited on the carrier tissue on the DanWeb assay device and is solidified this bicomponent fibre is bonded in this tissue.The purpose of doing like this is in order to obtain carrier to the excellent bonds effect of formed product thereon.This carrier tissue has constituted the underlayment of absorbent structure.In order to construct the middle basic unit of lower floor, in first forming head of machine, add 96gsm ND416 fine hair (Weyerhaeuser, Tacoma, WA) and 115gsm super absorbent polymer SXM70 (Stockhausen, Greensboro, NC).Then, in this process, the middle basic unit on upper strata is by add FoleyFluff (the Buckeye Technologies of 62gsm in second forming head, Memphis, TN), the bicomponent binder fibers T-255 of the super absorbent polymer SXM70 of 25gsm and 12gsm forms.At last, form basic unit by in the 3rd forming head, adding 42gsm Wellman 376 * 2 polyester fibers (its thickness is that 15 daniers/every fiber and length are 6mm).The latex A-181 of the last usefulness 6gsm of basic unit (Air Products, Allentown, PA) spraying, latex is with the concentration of 10% solids content.This sheet material is densified to the thickness of 2.6mm and is solidified.

Embodiment 9

Make absorbent structure by dry-press process on the DanWeb assay device.The mechanical performance of this structure and absorbent properties are described in table 5 and 6.This structure shows improved performance, and this is owing to the flexibility of optimal level, the combination of pliability and wet integrity.Three forming heads are used to make this absorbent structure.Form underlayment by adding 83gsm Foley Fluff and 7gsm bicomponent binder fibers T-255 (having thickness is 2.1 daniers/every fiber) in first forming head.By in second forming head, adding 110gsm Foley Fluff, 130gsm super absorbent polymer SP1186 (Stockhausen, Greensboro NC) forms middle basic unit with 15gsm bicomponent binder fibers T-255 (thickness with 2.1 daniers/every fiber).Form basic unit by in the 3rd forming head, adding 42gsm Wellman 376 * 2 polyester fibers (its thickness is that 15 daniers/every fiber and length are 6mm).The spraying of the latex A-181 of 8gsm of last basic unit with the concentration of 10% solids content.This sheet material is densified to the thickness of 5.2mm and is solidified.

Embodiment 10

Make absorbent structure by dry-press process on the DanWeb assay device.The mechanical performance of this structure and absorbent properties are described in table 5 and 6.This structure shows improved performance, and this is owing to the flexibility of optimal level, the combination of pliability and wet integrity.This product is applied on carrier upper berth at the Cellutissue 3024 of the Unit Weight with 18gsm.Before using, this tissue floods with 4gsm bicomponent binder fibers T-255, and this fiber has the thickness of 2.8 daniers/every fiber.This carrier tissue has constituted the underlayment of absorbent structure.In order to construct the middle basic unit of lower floor, in first forming head, add 80gsm ND416 fine hair (Weyerhaeuser, Tacoma, WA) and the super absorbent polymer SXM70 of 100gsm.By in second forming head, adding the Foley fine hair of 79gsm and the super absorbent polymer SXM70 of 38gsm, form the middle basic unit on upper strata with second forming head.The Wellman 376 * 2 poly-(ethylene glycol terephthalate) of the length by adding thickness with 15 daniers/every fiber and 6mm at the 3rd forming head forms basic unit.This fiber is to add with 38gsm.(aqueous solution DE) is with 10% solid concentration spraying for Hercules, Willmington from the top with Kymene 557H wet strength resin for this product.The solid target Unit Weight of Kymene is 7gsm on the net.Because elevated pressures in the basic unit and the difference between the lower pressure below the form wire have caused barometric gradient on formation structure, the solution of binding agent can be penetrated in the following basic unit to a certain extent, so Kymene can will go up basic unit and following basic unit bonds together.This product is through reaching the thickness of 2.6mm after rolling.

Embodiment 11

With three forming heads at M ﹠amp; J is purchased on the machine and makes the absorbability core by dry-press process.This product is applied on carrier upper berth at the Cellutissue 3024 of the Unit Weight with 18gsm.By in first and second forming heads, adding the ND416 fine hair of equivalent, super absorbent polymer SXM3950 (Stockhausen, Greensboro NC) forms underlayment with the bicomponent binder fibers T-255 with thickness of 2.8 daniers/every fiber.So the composition (by the gross weight of this basic unit) of the underlayment that forms is 23.2%ND416,48.2%SXM3950 and 2.6%T-255.Form middle basic unit by the ND416 of adding 38.1gsm in the 3rd forming head and the T-255 of 9gsm.The product Licontrol 381002-48 that forms like this, 48gsm synthesis of non-woven fabric (Jacob Holm Industries, Soultz, France) combination, the latter has constituted the last basic unit of this structure.Analyzed mechanical performance of this structure and absorbent properties.The result is summarised in that this structure shows improved performance in table 5 and 6, and this is owing to the flexibility of optimal level, the combination of pliability and wet integrity.

Embodiment 12

The structure of embodiment 8-11 is used to analyze wet integrity, flexibility and pliability.Obtain that the results are shown in Table 6.In table 6, give the result of the test of carrying out with several commodity diaper cores.

Data in the table 6 show that the absorbent structure of embodiment 8-11 has higher wet integrity, higher flexibility and the pliability of Geng Gao, with whole other tested absorbability cores Comparatively speaking.

Table 6

Absorbent structure	Wet integrity, mN/gsm	Flexibility, 1/J	Pliability, 1/N
				Embodiment
8	6.5	30.4	272.7
				Embodiment 9	12.3	37.5	235.5
Embodiment 10	8.1	22.1	259.9
				Embodiment 11	6.5	13.1	199.6
Embodiment A	0.8	10.1	175.5
				Embodiment E	4.2	12.4	196.7
Embodiment B	2.6	12.9	137.8
				Embodiment C	1.5	7.4	47.7
Embodiment D	1.3	5.6	40.2

Embodiment 13

Structure according to the program manufacturing of describing in embodiment 8-11 can be tested the rewetting amount in the method described in the embodiment 7 according to above.The results are shown in Table 7 for the rewetting retention rate of the structure of embodiment 8-11 and commodity absorbability core (embodiment E).Can find out that the rewetting retention rate of the structure of embodiment 8-11 is the same with the rewetting retention rate that is purchased structure (embodiment E) good or better.

Table 7

Absorbent structure	The rewetting retention rate, %
		Embodiment 1	97.3
Embodiment 2	83.3
		Embodiment 3	98.3
Embodiment 4	99.1
		Embodiment E	84.6

Table 5

Sample	Total surface area (cm 2)	Grand mean Unit Weight (gsm)	Grand mean core density (g/cc)	Grand mean core % SAP
					Embodiment D	398	472	0.31	43.0
Embodiment C	385	759	0.14	26.7
					Embodiment B	468	617	0.25	53.5
Embodiment E	260	547	0.11	44.9
					Embodiment A	360	649	0.26	43.4
Embodiment 8	320	380	0.15	36.8
					Embodiment 9	320	395	0.08	32.9
Embodiment 10	320	364	0.14	37.9
					Embodiment 11	320	387	0.21	58.1

Claims (52)

1. absorbent structure, it has the wet integrity that is higher than about 4.0mN/gsm, is higher than the flexibility of 8.0/J, is higher than the pliability of about 70/N, and exsiccant basically liquid receiving surface is provided after accepting certain amount of fluid, and this structure comprises:

A) go up synusia, it has last fluid receiving surface and lower surface and comprises:

I) comprise that this matrix fiber has the length of the about 15mm of about 2-with the last basic unit of the synthetic substrate fiber of adhesive bond;

Ii) realize the middle basic unit that fluid is communicated with last basic unit, this centre basic unit comprises natural fiber, superabsorbent particles and binding agent; With

Iii) realize the underlayment that fluid is communicated with middle basic unit, this underlayment comprises natural fiber and binding agent; With

B) go up the following synusia that synusia realizes that fluid is communicated with this, this time synusia has upper surface and lower surface and comprises at least one basic unit, and this basic unit comprises natural fiber, superabsorbent polymer particles and binding agent,

Its at the middle and upper levels the surface area that lower surface had of sheet be lower than following synusia upper surface area about 80%;

C) upward the Unit Weight of the last basic unit of synusia is that about 20gsm is to about 120gsm;

D) on last synusia in the basic unit binder content (percetage by weight) be about 5% to about 20%;

E) upward the Unit Weight of the middle basic unit of synusia is that about 50gsm is to about 1000gsm;

F) binder content (percetage by weight) is about 1%-about 10% in the middle basic unit of last synusia;

G) upward the Unit Weight of the underlayment of synusia is that about 10gsm is to about 150gsm;

H) binder content (percetage by weight) is about 5%-about 15% in the underlayment of last synusia;

I) superabsorbent particles content (percetage by weight) is lower than the content of superabsorbent particles in the infra synusia in last synusia;

J) upward the apparent density of synusia is lower than the apparent density of synusia down;

K) Unit Weight of synusia is that about 100gsm is to about 1000gsm down;

L) apparent density of synusia is that about 0.15g/cc is to about 0.25g/cc down;

M) binder content (percetage by weight) is about 1%-about 8% in the infra synusia; With

N) this time synusia contains at least 30% superabsorbent particles of the Unit Weight that is equivalent to following synusia.

2. the absorbent structure of claim 1, wherein the length of synthetic substrate fiber is about 4 to about 12mm.

3. the absorbent structure of claim 1, wherein the synthetic substrate fiber is about 30 daniers of about 2-/every fiber.

4. the absorbent structure of claim 3, wherein the synthetic substrate fiber is about 15 daniers of about 6-/every fiber.

5. the absorbent structure of claim 1, wherein this synthetic substrate fiber is selected from polyethylene, polypropylene, polyester, polyamide, cellulose acetate, rayon fiber and their mixture.

6. the absorbent structure of claim 1, wherein this binding agent is selected from latex adhesive, thermoplastic powder, thermoplastic fibre, bicomponent fibre and their mixture.

7. the absorbent structure of claim 1, wherein binding agent is selected from polyamide-polyamine epichlorohydrin adducts, cationic starch, dialdehyde starch, poly-(vinyl alcohol), chitosan and their mixture.

8. the absorbent structure of claim 1, wherein natural fiber is selected from Cotton Gossypii, softwood pulp, bardwood pulp, Caulis et Folium Oryzae, gram husband fiber, the cellulose fibre, keratin fiber and their mixture that carry out modification by chemistry, machinery and/or heat treatment.

9. the absorbent structure of claim 1, its at the middle and upper levels the Unit Weight of the last basic unit of sheet be that about 30gsm is to about 60gsm.

10. the absorbent structure of claim 1, wherein on last synusia in the basic unit content of synthetic substrate fiber be the about 99wt% of about 50-.

11. the absorbent structure of claim 10, wherein on last synusia in the basic unit content of synthetic substrate fiber be the about 90wt% of about 75-.

12. the absorbent structure of claim 1, its at the middle and upper levels the Unit Weight of the middle basic unit of sheet be about 80gsm to about 300gsm.

13. the absorbent structure of claim 1, wherein in the middle basic unit of last synusia the content of superabsorbent polymer particles be on the about 60wt% of about 5-of synusia weight.

14. the absorbent structure of claim 13, wherein the content of superabsorbent polymer particles is the about 50wt% of about 20-in the middle basic unit of last synusia.

15. the absorbent structure of claim 1, its at the middle and upper levels the underlayment of sheet be the layer of air lay.

16. the absorbent structure of claim 1, its at the middle and upper levels the underlayment of sheet be the cellulose tissue of wet-laying.

17. the absorbent structure of claim 1, the apparent density of wherein descending synusia are that about 0.15g/cc is to about 0.25g/cc.

18. the absorbent structure of claim 1, the Unit Weight that wherein descends synusia are that about 150gsm is to about 400gsm.

19. the absorbent structure of claim 1, wherein the content of superabsorbent polymer particles is the about 80wt% of about 30-in the infra synusia.

20. the absorbent structure of claim 19, wherein the content of superabsorbent polymer particles is the about 60wt% of about 40-in the infra synusia.

21. the absorbent structure of claim 1, wherein whole layers of each synusia are all to gather together in this forming process.

22. the absorbent structure of claim 1, wherein each synusia is that the air lay method forms, and wherein said air lay method is the overall process that may further comprise the steps:

A) raw material is added in one or more forming heads to form lamella;

B) described lamella shop is spread on the carrier;

C) be cured with minimum pressure and not necessarily

D) roll described lamella.

23. the structure of claim 1, wherein superabsorbent polymer particles is placed at least one basic unit of the last synusia in vertical discrete channel of the length direction of core, these passages comprise about 70%-100% superabsorbent polymer particles, and these passages are comprised that the adjacency channel of fiber and binding agent separates.

24. the structure of claim 1, wherein superabsorbent polymer particles is placed in the following synusia in vertical discrete channel of the length direction of core, these passages comprise about 70%-100% superabsorbent polymer particles, and these passages are comprised that the adjacency channel of fiber and binding agent separates.

25. an absorbent structure, it has the wet integrity that is higher than about 4.0mN/gsm, is higher than the flexibility of 8.0/J, is higher than the pliability of about 70/N, and exsiccant basically liquid receiving surface is provided after accepting certain amount of fluid, and this structure comprises:

A) go up synusia, it has last fluid receiving surface and lower surface and comprises:

I) comprise that this matrix fiber has the length of the about 15mm of about 2-with the last basic unit of the synthetic substrate fiber of adhesive bond;

Ii) realize the middle basic unit that fluid is communicated with last basic unit, this centre basic unit comprises natural fiber and superabsorbent particles; With

Iii) realize the underlayment that fluid is communicated with middle basic unit, this underlayment comprises natural fiber and binding agent; With

B) realize the following synusia that fluid is communicated with last synusia, this time synusia has upper surface and lower surface and comprises:

I) go up basic unit, it comprises natural fiber and binding agent; With

Ii) underlayment, it comprises natural fiber, superabsorbent polymer particles and binding agent, wherein:

C) surface area that lower surface had of going up synusia be lower than synusia down upper surface area about 80%;

D) the last basic unit of going up synusia does not demonstrate the fluid core basically and soaks energy-absorbing power;

E) upward the Unit Weight of the last basic unit of basic unit is that about 20gsm is to about 120gsm;

F) on last synusia in the basic unit binder content (percetage by weight) be about 5% to about 20%;

G) upward the Unit Weight of the middle basic unit of synusia is that about 50gsm is to about 1000gsm;

H) binder content (percetage by weight) is about 1%-about 10% in the middle basic unit of last synusia;

I) upward the Unit Weight of the underlayment of synusia is that about 10gsm is to about 150gsm;

J) binder content (percetage by weight) is about 5%-about 15% in the underlayment of last synusia;

K) content of superabsorbent particles is lower than the content of superabsorbent particles in the infra synusia in last synusia;

L) this time synusia contains at least 30% superabsorbent particles of total Unit Weight of being equivalent to following synusia.

M) about 0% to about 20% superabsorbent particles is contained in the last basic unit of following synusia, based on the Unit Weight of the last basic unit that descends synusia;

N) Unit Weight of synusia is that about 100gsm is to about 1000gsm down;

O) apparent density of synusia is that about 0.15g/cc is to about 0.25g/cc down;

P) upward the apparent density of synusia is lower than the apparent density of synusia down; With

Q) binder content (percetage by weight) of synusia is about 1%-about 8% down.

26. the absorbent structure of claim 25, wherein the length of synthetic substrate fiber is about 4 to about 12mm.

27. the absorbent structure of claim 25, wherein the synthetic substrate fiber is about 30 daniers of about 2-.

28. the absorbent structure of claim 27, wherein the synthetic substrate fiber is about 15 daniers of about 6-.

29. the absorbent structure of claim 25, wherein this synthetic substrate fiber is selected from polyethylene, polypropylene, polyester, polyamide, cellulose acetate, rayon fiber and their mixture.

30. the absorbent structure of claim 25, wherein this binding agent is selected from latex adhesive, thermoplastic powder, thermoplastic fibre, bicomponent fibre and their mixture.

31. the absorbent structure of claim 25, wherein binding agent is water solublity or water-dispersible polymers binding agent.

32. the absorbent structure of claim 25, wherein natural fiber is selected from Cotton Gossypii, softwood pulp, bardwood pulp, Caulis et Folium Oryzae, gram husband fiber, the cellulose fibre, keratin fiber and their mixture that carry out modification by chemistry, machinery and/or heat treatment.

33. the absorbent structure of claim 25, its at the middle and upper levels the Unit Weight of the last basic unit of sheet be about 30gsm to about 60gsm.

34. the absorbent structure of claim 25, wherein on last synusia in the basic unit content of synthetic substrate fiber be the about 99wt% of about 50-.

35. the absorbent structure of claim 25, wherein on last synusia in the basic unit content of synthetic substrate fiber be the about 90wt% of about 75-.

36. the absorbent structure of claim 25, its at the middle and upper levels the Unit Weight of the middle basic unit of sheet be about 80gsm to about 300gsm.

37. the absorbent structure of claim 25, wherein in the middle basic unit of last synusia the content of superabsorbent polymer particles be on the about 60wt% of about 5-of synusia weight.

38. the absorbent structure of claim 25, wherein in the middle basic unit of last synusia the content of superabsorbent polymer particles be on the about 50wt% of about 20-of synusia weight.

39. the absorbent structure of claim 25, the Unit Weight that wherein descends synusia are that about 150gsm is to about 400gsm.

40. the absorbent structure of claim 25, wherein the total content of superabsorbent polymer particles is the about 80wt% of about 30-in the infra synusia.

41. the absorbent structure of claim 25, wherein the content of superabsorbent polymer particles is the about 60wt% of about 40-in the infra synusia.

42. the absorbent structure of claim 25, its at the middle and upper levels the underlayment of sheet be the layer of air lay.

43. the absorbent structure of claim 25, its at the middle and upper levels the underlayment of sheet be the cellulose tissue of wet-laying.

44. the absorbent structure of claim 25, the Unit Weight that wherein descends the last basic unit of synusia are that about 10gsm is to about 150gsm.

45. the absorbent structure of claim 25, the Unit Weight that wherein descends the last basic unit of synusia are that about 15gsm is to about 90gsm.

46. the absorbent structure of claim 25, wherein whole basic units of each synusia all gather together in this forming process.

47. the absorbent structure of claim 25, it is formed by the air lay method, and wherein said air lay method is the overall process that may further comprise the steps:

A) raw material is added in one or more forming heads to form lamella;

B) described lamella shop is spread on the carrier;

C) be cured with minimum pressure and not necessarily

D) roll described lamella.

48. the structure of claim 25, wherein superabsorbent polymer particles is placed at least one basic unit of the last synusia in vertical discrete channel of the length direction of core, these passages comprise about 70%-100% superabsorbent polymer particles, and these passages are comprised that the adjacency channel of fiber and binding agent separates.

49. the structure of claim 25, wherein superabsorbent polymer particles is placed at least one basic unit of the following synusia in vertical discrete channel of the length direction of core, these passages comprise about 70%-100% superabsorbent polymer particles, and these passages are comprised that the adjacency channel of fiber and binding agent separates.

50. absorbent structure, it comprises:

A) go up synusia, comprising:

I) go up basic unit, it comprises with latex comes agglutinating polyester matrix fiber with the amount of the 15-25wt% that is equivalent to substrate weight, this matrix fiber has length and about 9 the thickness to about 15 daniers/every piece fiber of about 4mm to about 8mm, and the Unit Weight of last basic unit is about 40 to about 60gsm;

Ii) realize the middle basic unit that fluid is communicated with last basic unit, this centre basic unit comprises cork fine hair, superabsorbent polymer particles and binder fibre, the content of superabsorbent polymer particles is about 30-40% of the Unit Weight of middle basic unit, the content of binder fibre be in the middle of the Unit Weight of about 6 to about 12% and middle basic unit of Unit Weight of basic unit be about 150 to arrive about 200gsm;

Iii) realize the underlayment that fluid is communicated with middle basic unit, it comprises cork fine hair and binder fibre, and the content of binder fibre is that the Unit Weight of about 8 to about 16% and underlayment of the Unit Weight of underlayment is about 60 to arrive about 120gsm; With

B) realize the following synusia that fluid is communicated with last synusia, this time synusia comprises:

I) go up basic unit, comprise cork fine hair and binder fibre, the content of binder fibre is that about 10 to about 25% and Unit Weight of the upward Unit Weight of basic unit is about 20 to about 60gsm;

Ii) underlayment comprises cork fine hair, superabsorbent polymer particles and binder fibre, and the content of superabsorbent polymer particles is Unit Weight about 50 to 80% of underlayment, the content of binder fibre be underlayment Unit Weight about 2 to 5%; With

Iii) the cellulose tissue has formed time synusia on it,

Wherein:

C) have the last synusia of the surface area adjacent with following synusia, this surface area be the opposed face of synusia down long-pending about 40% to 60%;

D) upward the density of synusia is about 0.05 to about 1.0g/cc;

E) density of synusia is about 0.15 to 0.3g/cc down.

51. absorbent structure, it comprises:

A) go up synusia, contain:

I) go up basic unit, it comprises with latex comes agglutinating polyester matrix fiber with the amount of the 15-25wt% that is equivalent to substrate weight, this matrix fiber has length and about 9 the thickness to about 15 daniers/every piece fiber of about 4mm to about 8mm, and the Unit Weight of last basic unit is about 40 to about 60gsm;

Ii) realize the middle basic unit that fluid is communicated with last basic unit, this centre basic unit comprises cork fine hair, superabsorbent polymer particles and binder fibre, the content of superabsorbent polymer particles is about 40-60% of the Unit Weight of middle basic unit, the content of binder fibre be in the middle of the Unit Weight of about 6% to about 12% and middle basic unit of Unit Weight of basic unit be about 200 to arrive about 280gsm;

Iii) realize the underlayment that fluid is communicated with middle basic unit, it comprises cork fine hair and binder fibre, and the content of binder fibre is that the Unit Weight of about 8 to about 16% and underlayment of the Unit Weight of underlayment is about 60 to arrive about 120gsm; With

B) realize the following synusia that fluid is communicated with last synusia, this time synusia comprises:

I) go up basic unit, comprise cork fine hair and binder fibre, the content of binder fibre is that about 10 to about 25% and Unit Weight of the upward Unit Weight of basic unit is about 20 to about 60gsm;

Ii) underlayment, comprise cork fine hair, superabsorbent polymer particles and binder fibre, the content of superabsorbent polymer particles be underlayment Unit Weight about 40% to about 60%, the content of binder fibre is that the Unit Weight of about 2% to 5% and underlayment of the Unit Weight of underlayment is about 200 to about 350gsm; With

Iii) the cellulose tissue has formed time synusia on it, wherein:

C) have the last synusia of the surface area adjacent with following synusia, this surface area be the opposed face of synusia down long-pending about 40% to 60%;

D) upward the density of synusia is about 0.05 to about 1.0g/cc;

E) density of synusia is about 0.15 to 0.3g/cc down.

52. an absorbent structure, it has the wet integrity that is higher than about 4.0mN/gsm, is higher than the flexibility of 8.0/J, is higher than the pliability of about 70/N, and exsiccant basically liquid receiving surface is provided after accepting certain amount of fluid, and this structure comprises:

A) go up synusia, it has last fluid receiving surface and lower surface and comprises:

I) comprise that this matrix fiber has the length of the about 15mm of about 2-with the last basic unit of the synthetic substrate fiber of adhesive bond;

Ii) realize the middle basic unit that fluid is communicated with last basic unit, this centre basic unit comprises natural fiber, superabsorbent particles and binding agent; With

Iii) realize the underlayment that fluid is communicated with middle basic unit, this underlayment comprises natural fiber and binding agent; With

B) go up the following synusia that synusia realizes that fluid is communicated with this, this time synusia has upper surface and lower surface and comprises at least one basic unit, and this basic unit comprises natural fiber, superabsorbent polymer particles and binding agent,

Its at the middle and upper levels the surface area that lower surface had of sheet be lower than following synusia upper surface area about 80%.

Images